1. Field of the Invention
The present invention relates to a plural synthesizer controlling system for a personal handyphone system wherein the number of control lines from a modem IC to two 1st local units of a personal handyphone system (PHS) terminal adapted for 1-frame 2-slot transmission/reception is reduced and a plural synthesizer controlling method for the same.
2. Description of the Related Art
A local unit of a PHS terminal to which the present invention relates is used particularly for frequency conversion of transmission/reception.
A local unit of the type mentioned usually functions sufficiently if one 1st local unit is provided in a PHS terminal. In recent years, however, as popularization of mobile computing proceeds, high speed data communication is demanded also for mobile computing.
Therefore, in order that a PHS system which is high in transmission speed and is connected to an ISDN may allow high speed data communication up to 64 Kbps (kilo bit per second) which is the transmission speed of the ISDN, it operates to perform data communication by 1-frame 2-slot transmission/reception.
FIG. 1 shows a block diagram of a local unit adapted for two slots according to the prior art.
Since the prior art described above operates to perform data communication by 1-frame 2-slot transmission/reception, it is disadvantageous in that 1st local units must be prepared for two slots.
The prior art is disadvantageous also in that, since it includes two 1st local units, synthesizers of the local units must be controlled separately from each other, and this increases the number of control lines.